Various solutions have already been advocated in order to remedy the difficulties created by the carriage displacements.
Some of them consist in providing a counter-weight exerting on the carriage relief efforts the resultant of which is variable in position according to the position of the centre of gravity of the carriage and creating a tipping moment which is antagonistic to that caused by the carriage displacements.
A further solution disclosed in French Pat. No. 75.03217 (published under No. 2.299.117) filed on Feb. 3, 1975, to Soci/e/ t/e/ HURE, consists in providing one or several cam-shaped bars, supported by the carriage, co-acting with rollers carried by the carriage support, the bars and rollers being disposed and having a configuration such as to apply to the anterior portion of the ram a force in the upward direction and balancing the weight of the overhanging portion of the carriage.